Warpage in thin microelectronic package structures has been a challenge in the fabrication of packaged devices. Temperature coefficients of thermal expansion (CTE) may differ between a device and a package substrate, which contributes to the problem. Temperature processing, such as a solder reflow process, may contribute to a significant amount of warpage, which in turn can cause opens in circuitry, resulting in loss of yield and reduced reliability of a packaged device. Stiffeners, such as metal stiffeners, can be employed which may reduce warpage in thin packages during temperature processing.